Bison Return to Iowa's Native Prairie

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DES MOINES, Iowa, October 20, 2008 (ENS) - This week, the Nature Conservancy in Iowa will welcome a small herd of 30 bison to Broken Kettle Grassland Preserve in the globally rare Loess Hills, the largest contiguous native prairie in the state.

These bison are coming from the conservancy's Lame Johnny Creek Ranch, in South Dakota, which is up for sale. They form a maternal grouping of bison that will serve as a starter herd for the Iowa plains.

Final preparations are underway for their arrival. Iowa and South Dakota staff are working through the final details of the transfer plan, together with state veterinarians, to ensure a safe, stress-free trip for the animals.

Final touches are being placed on the conservancy's corral and high-tensile electric fence. Native prairie hay is ready to go into the trap pasture where the bison will be held for their first few days in Iowa. Woven wire fencing is secured around the trap pasture. Gates are double checked.

These animals will be in the corral for the first week, then in the west half of the trap pasture, then have access to the entire 125-acre trap pasture for winter.

The herd originated from the Wind Cave National Park herd and is historically and genetically valuable, the conservancy says. They have shown no evidence of cattle introgression or cattle genes as determined by current DNA testing techniques.

A recently completed study by Texas A&M University scientists into the genetics and health of 10 federal herds found the herd at Wind Cave National Park to be the only disease free, genetically pure federal herd in the country.

More than 150 years ago, bison were a natural and integral part of the prairie ecosystem before Europeans settled the vast central tallgrass prairie. Once 50 million animals roamed the western ranges, but they were killed until by the 1890s only about 2,000 animals remained.

Today it is estimated that the total herd size is in the 500,000 animal range, about half in Canada and half in the United States.

Bison grazing allows for a more diverse mix of prairie species and a diverse structure critical for the survival of the animals dependent on prairie habitat.

"Bison provide a different effect on the ground. We expect a more wide-spread disturbance pattern with better pasture utilization," said Scott Moats, the conservancy's Broken Kettle Grasslands preserve manager.

"With bison, we'll see a change in the plant community. Our prairie is ready for them," he said.

And while the bison will benefit the prairie, the conservancy is working closely with Texas A&M scientists to determine the best course of action to conserve the genetic integrity of these unique bison at Broken Kettle Grasslands.

Broken Kettle Grasslands is located in the northern portion of the Loess Hills, which rise 200 feet above the Missouri River Valley, a narrow band of wrinkled bluffs that cover some 650,000 acres along the state''s western border. It is 25 minutes northwest of Sioux City, Iowa.

This region supports some of Iowa''s best examples of tallgrass prairie. Today, less than one percent of the original tallgrass prairie remains, making it one of North America''s most endangered ecosystems.

Large-scale prairie restoration efforts are working in Iowa, said Moats. The arrival of these big, native grass-eaters is an exciting step in the conservancy's long term goals for Iowa's largest remaining prairie.